工艺参数对医用注射器注射成型结晶度与壁厚均匀性的影响

发布时间：2018-03-07 22:25

本文选题：薄壁注射成型　切入点：剪切速率　出处：《南昌大学》2016年硕士论文　论文类型：学位论文

【摘要】：与常规塑件注射成型不同,在薄壁塑件注射成型中,由于薄壁塑件制品的较薄壁厚,聚合物熔体在充模过程中会很快冷却,促使聚合物熔体更容易凝固冻结,导致成型生产难度加大,容易产生各种成型质量缺陷,严重影响了塑件产品的品质质量。聚合物注射成型过程是一种包含高度非线性、时变性的多工艺参数影响的复杂成型过程,其每个工艺参数对成型塑件产品质量的好坏都具有程度各异的影响。因此分析研究注射成型生产过程中工艺参数条件对塑件产品的品质质量的影响并对工艺参数条件组合进行优化,是提高成型薄壁塑件产品质量的一条行之有效的措施。本文采用聚合物注射成型模流仿真分析软件Autodesk Moldflow Insight的流动分析模块(Filling Packing,也可称为Flow)对聚合物注射成型过程中聚合物熔体的充模流动行为进行CAE有限元数值仿真模拟计算,研究了熔体温度、模具温度、注射时间和保压压力四个成型工艺参数对医用注射器针筒成型时最大剪切速率分布场的影响,分析结果表明,在聚合物熔体充模流动方向上,靠近浇口位置附近处的剪切速率远大于其他位置的剪切速率,在距浇口0~10mm这段距离内,随着距离的增加,最大剪切速率迅速减小。而从距离浇口10mm处至塑件产品的末端处,最大剪切速率的改变不甚明显。在聚合物熔体充模厚度方向上,熔体芯层处的剪切速率最小,向表层方向逐渐增大,呈现比较畸形的“M”状,在距离表面层大约0.1mm处到达剪切速率的最大值,接着再往表层减小直至表面层。最后基于最大剪切速率分布场结果对结晶度做出了预测。选取了熔体温度、模具温度、注射时间和保压压力为实验的输入设计变量,以垂直于装配方向的最大体积收缩变形和最大型芯偏移为响应输出优化指标,通过响应曲面中心复合试验设计方法耦合CAE有限元数值仿真模拟试验,利用实验数据分析软件Design-Expert8.0对响应实验结果进行非线性回归拟合输入设计变量与响应变量之间的二次响应曲面数学模型,研究分析了成型工艺参数条件对医用注射器针筒成型质量的影响显著性及影响规律,对响应输出目标进行了多目标优化求解,获取最优成型工艺参数组合,在对其进行仿真模拟验证了准确度后,将其应用于实际生产,成型出符合厂家质量需求的医用注射器针筒。
[Abstract]:Different from the conventional injection molding of plastic parts, in the injection molding of thin-walled plastic parts, because of the thicker thin-walled products, the polymer melts will be cooled quickly during the filling process, which makes the polymer melt solidify and freeze more easily. The process of polymer injection molding is a kind of highly nonlinear process, which leads to more difficulty in molding production and easy to produce all kinds of quality defects, which seriously affect the quality of plastic parts. The time-varying effects of multiple process parameters on the complex molding process, Each process parameter has different influence on the quality of plastic parts. Therefore, the influence of process parameters on the quality and quality of plastic parts in injection molding process is analyzed and studied. The condition combination is optimized, It is an effective measure to improve the product quality of forming thin-walled plastic parts. In this paper, the flow analysis module of polymer injection molding simulation software Autodesk Moldflow Insight is used in polymer injection molding process. The mold filling behavior of polymer melt was simulated by CAE finite element method. The effects of melt temperature, mold temperature, injection time and pressure holding pressure on the maximum shear rate distribution of the syringe were studied. The results showed that the polymer melt was filled in the direction of mold filling. The shear rate near the gate position is much higher than that near the other position, and the maximum shear rate decreases rapidly with the increase of the distance from the gate to the end of the plastic product, and from the gate to the end of the plastic product, the maximum shear rate decreases rapidly with the increase of the distance from the gate to the end of the plastic product. The change of the maximum shear rate is not obvious. In the direction of the filling thickness of polymer melt, the shear rate at the core layer of the polymer is the smallest, and gradually increases towards the surface layer, showing a more deformed "M" shape. The maximum shear rate is reached at a distance of about 0.1 mm from the surface layer, and then decreases to the surface layer. Finally, the crystallinity is predicted based on the results of the maximum shear rate distribution. The injection time and pressure holding pressure are the input design variables of the experiment. The maximum volume shrinkage deformation and the largest core offset perpendicular to the assembly direction are taken as the response output optimization index. The CAE finite element numerical simulation experiment is coupled by the complex test design method of the center of the response surface. A mathematical model of Quadric response surface between the input variables and the response variables is fitted by using the experimental data analysis software Design-Expert8.0. The influence of molding process parameters on the forming quality of syringe syringes is studied and analyzed. The multi-objective optimization solution of the response output target is carried out to obtain the optimal forming process parameters. After the accuracy is verified by simulation and simulation, the syringe syringe which meets the quality requirement of the manufacturer is formed by applying it to the actual production.
【学位授予单位】：南昌大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TH788;TQ320.662

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